Musical Memory Mapper

Documentation

Version 2014-12-18

by GDX

Thanks to Ericb59

IndexIntroduction...........................................................................................................................................................3Registers description..............................................................................................................................................4

Registers accessible via I/O ports.....................................................................................................................4Memory Mapper's registers ports................................................................................................................4Control Register Port of MMM...................................................................................................................5Write port to SN76489AN registers.............................................................................................................5

Tone generators registers........................................................................................................................5Control Registers of volumes.................................................................................................................7Noise Generator control register.............................................................................................................8

Registers accessible via access to an address....................................................................................................9Control Register of MMM...........................................................................................................................9Memory Mapper Registers of MMM..........................................................................................................9

Programming.......................................................................................................................................................10Auto-detection of MMM................................................................................................................................10Get the current status of a Slot........................................................................................................................12

Additional Information........................................................................................................................................13Connected directly the PCB to an expansion BUS.........................................................................................13Compatibility list............................................................................................................................................15

Introduction

The Musical Memory Mapper (MMM) cartridge is a standard 1024KB memory extension for MSX1, MSX2, MSX2 + and MSX Turbo R.

However, it has other features. A SN76489AN sound chip used in various game consoles of the 80s has been added. The purpose is, among others, to run on MSX the games of other consoles that have this sound chip as main diference with the MSX computers. Softwares are provided to run games of the Sega SG-1000 and Colecovision, with identical sound as the original!

The Musical Memory Mapper has also a write protection function and the ability to manage its memory regardless of other Memory Mapper to make easier launch of MSX ROM fles.

Registers description

The cartridge has registers accessible by two diferent ways except those of SN76489AN.

Registers accessible via I/O ports

Memory Mapper's registers ports :

These registers are the standard Memory Mapper registers, and work at the same time and in the same way as all Memory Mapper on MSX.

WriteBank Port 7 6 5 4 3 2 1 0

0000h~3FFFh FCh - - Page (0~31)

4000h~7FFFh FDh - - Page (0~31)

8000h~BFFFh FEh - - Page (0~31)

C000h~FFFFh FFh - - Page (0~31)

Bits 6 and 7 are ignored. They can be set or reset.

Note: MMM initializes Memory Mapper pages on each memory bank of 0000h~3FFFh, 4000h~7FFFh, 8000h~BFFFh and C000h~FFFFh in the order 3, 2, 1, 0 at MSX startup to provide a full compatibility even on MSX1. A standard Memory Mapper does not initialize its pages. This is the BIOS or the MSX-DOS2 that does it during the system initialization. The MSX1 Bios does not take into account the Memory Mapper. This may cause a crash at launch a program if a standard Memory Mapper was chosen as the main RAM.

Control Register Port of MMM:

Only bit 7 of this register is accessible via I/O port.

Write onlyPort 7 6 5 4 3 2 1 0

3Ch BA - - - - - - -

BA : Enables access to registers via access to an address.

Write port to SN76489AN registers:

The SN76489AN has four channels sound (three programmable tone generators and one noise generator which can also generate a periodic pulse type waveform).

The SN76489A has 8 internal registers which are used to control the 3 tone generators and the noise source. During all data transfers to the SN76489A, the frst byte contains a 3 bits feld which determines the channel and the control/attenuation.

The volume of each channel can be controlled separately on 16 levels (high until silence) using registers 1, 3, 5 and 7.

Each byte Written to sound chip port determines either the register to be used with its value or the upper part of the value of frequency.

Tone generators registers:

Tone generator frequency is coded on 10 bits thus it is sent on 2 bytes to send one after the other. The output frequency is square with some imperfections.

First byte:

Write onlyPort 7 6 5 4 3 2 1 0

3Fh 1 R2 R1 R0 D3 D2 D1 D0

D0~D3: Least signifcant 4 bits of frequency value.R0~R2: Tone control register number

000 = Tone frequency for channel 1010 = Tone frequency for channel 2100 = Tone frequency for channel 3110 = Noise control (channel 4)

Bit 7: Set to indicate that this is an access to the register of sound control

The second byte contains the most signifcant bits of wave value:

Write onlyPort 7 6 5 4 3 2 1 0

3Fh 0 - D9 D8 D7 D6 D5 D4

D4~D9: Most signifcant 6 bits of frequency valueBit 6: Unused

Bit 7: Reset to indicate that this is the most signifcant bits of frequency value

Use:

To write the frequency value, you need to send the frst byte that contains the 4 least signifcant bits of the value of the wave and destination and the second of the rest of the frequency value.

So if we want a frequency tone at 135 Hz (11 0011 1010 b) on channel 1, we need to do as in the following example.

First, we write the control word with least signifcant 4 bits of the frequency value:

LD A,10001010bOUT (3Fh),A

Then, most signifcant 6 bits of the frequency value:

LD A,00110011bOUT (3Fh),A

The frequency can be calculated by the following:

f = 3579545 / 32n

f is the output frequency and n is the binary 10-bit value.

Notes Frequency Conversion Table (Hz ↔ hexadecimal):

Hz Hex Hz Hex Hz Hex Hz Hex Hz Hex

A 110.00 3F8 220.00 1FC 440.00 0FE 880.00 07F 1760.0 03F

A#/Bb 116.54 3BF 233.08 1DF 466.16 0EF 932.33 077 1864.6 03B

B 123.47 389 246.94 1C4 493.88 0E2 987.77 071 1975.5 038

C 130.81 356 261.63 1AB 523.25 0D5 1046.5 06A 2093.0 035

C#/Db 138.59 327 277.18 193 554.36 0C9 1108.7 064 2217.5 032

D 146.83 2F9 293.66 17C 587.33 0BE 1174.7 05F 2349.3 02F

D#/Eb 155.56 2CE 311.13 167 622.25 0B3 1244.5 059 2489.0 02C

E 164.81 2A6 329.63 153 659.25 0A9 1318.5 054 2637.0 02A

F 174.61 280 349.23 140 698.46 0A0 1396.9 050 2793.8 028

F#/Gb 185.00 25C 370.00 12E 739.99 097 1480.0 04B 2960.0 025

G 196.00 23A 391.99 11D 783.99 08E 1568.0 047 3136.0 023

G#/Ab 207.65 21A 415.30 10D 830.61 086 1661.2 043 3322.4 021

Note: The frequency of middle C is 523.25 Hz. The frequency of the same note an octave higher is 1046.5 Hz.

Control Registers of volumes:

To control the volume, a single byte has to be sent.

Write onlyPort 7 6 5 4 3 2 1 0

3Fh 1 R2 R1 R0 V3 V2 V1 V0

V0~V3: Volume value0000 = Maximum volume0001 = Attenuation of 2dB0010 = Attenuation of 4dB0100 = Attenuation of 8dB1000 = Attenuation of 16dB1111 = Silence

R0~R2: Register number of volumes control001 = Tone volume for the channel 1011 = Tone volume for the channel 2101 = Tone volume for the channel 3111 = Noise volume (channel 4)

Bit 7: Reset to indicate that this is an access to volume control register.

Example:

Here is a routine in assembler to mute the sound of the four channels.

LD A,09FhOUT (3Fh),A ; channel 1LD A,0BFhOUT (3Fh),A ; channel 2LD A,0DFhOUT (3Fh),A ; channel 3LD A,0FFhOUT (3Fh),A ; channel 4

The equivalent in Basic.

OUT&H3F,&H9F:OUT&H3F,&HBF:OUT&H3F,&HDF:OUT&H3F,&HFF

Noise Generator control register:

The noise generator consists of a noise source that is a shift register with an exclusive ORfeedback network. The feedback network has provisions to protect the shift register from being locked in the zero state. It also takes a single byte.

Format:

Write onlyPort 7 6 5 4 3 2 1 0

3Fh 1 1 1 0 - FB NF1 NF0

NF1~NF0: Shift rate control

00 = N/51201 = N/102410 = N/204811 = Tone generator of channel 3

You can use the output of the tone generator 3 to do interesting efects. If you sweep the frequency of the sound of the voice generator 3, it will cause a nice sweeping efect on the noise.In general, this mode is used to reduce tone generator 3 with only the noise output as source.

FB: Feedback control

0 = Periodic noise1 = White noise

The periodic noise is interesting. Depending on the frequency, it can seem verytonal and smooth.

The volume works in the same manner as for other channels.

Registers accessible via access to an address

The MMM cartridge has registers accessible by reading or writing to assigned address. Access the registers in this way allows you to control the functions of the cartridge independently. For example, owners of two same cartridges may control one by one eachsound chip.

Control Register of MMM:

The frst writing to this register enables the sound chip. This produces a parasitic noise because SN76489AN registers can be initialized only by software. To avoid this, it's necessary to execute a routine to mute the volume of 4 voices immediately after the activation of SN76489AN. (See example at “Control Registers of volumes”)

Read / WriteAddress 7 6 5 4 3 2 1 0

803Ch / 403Ch* BA SN I/O - P3 P2 P1 P0

P0: Enable write protect bank 0000h~3FFFh.P1: Enable write protect bank 4000h~7FFFh.P2: Enable write protect bank 8000h~BFFFh.P3: Enable write protect bank C000h~FFFFh.Bit 4: Unused.I/O: The bit 5 is used to disable access to the registers of the cartridge by the I/O

ports. This allows to use the cartridge completely independent. This is useful inthe case where an other same cartridge is inserted in another cartridge port. When this bit is set to 1, bit 7 also goes to 1 and remains in this state until the bit 5 is reseted. Access to internal registers are permanent at the addresses 803Ch and 80FCh ~ 80FFh but if P3 is set to 1, access to registers will be at the 403Ch and 40FCh~40FFh.The I/O port 3Fh is not afected by the state of this bit, it will still be possible toenable or disable this port with bit 6.

SN: Enables 3Fh port to control the SN76489AN.BA: Reset to disable access to records via access to an address.

* These addresses have mirrors each next 100h on the same bank memory of the cartridge slot.

Memory Mapper Registers of MMM:

IThese registers are used to manage the Memory Mapper MMM independently of other Memory Mapper via the following addresses.

Read / WriteBank Address 7 6 5 4 3 2 1 0

0000h~3FFFh 80FCh* - - Page (0~31)

4000h~7FFFh 80FDh* - - Page (0~31)

8000h~BFFFh 80FEh* - - Page (0~31)

C000h~FFFFh 80FFh* - - Page (0~31)

Bits 6 and 7 are ignored. They will be at 1 at reading.

* These addresses have mirrors each next 100h on same bank memory of the cartridge slot.

Programming

Auto-detection of MMM

This assembler routine will allow you to fnd the cartridge port (or slot) in which MMM is inserted. This routine is necessary to activate the sound chip or using precisely his memory.

; Name: mmm_srch;; Input: H = 080h (or 040h) (Significant byte of the memory bank address); B = 16 (Possible number of secondary Slot);; Output: A = Slot Number in the form F000SSPP (0FFh if MMM is not found); B = Remaining iterations number;; Modify: All registers;; Size: 65 Bytes;; Note: The routine can be called multiple times to complete research in all; slots until B is set to 0 or until A is set to 0FFh.;; Warning: The routine does not replace the original slot after the search.;

mmm_srch: ld l,0FFh ; HL = Access address to Memory Mapper register

mmm_srch_loop:

push hlld a,b ; The Slot it is extended?dec aand 3

ld hl,mnromadd a,lld l,a

ld a,bdec aor (hl)

pop hl

jp m,ext_slt ; Jump if the slot is extended

and %00001111cp 4jr nc,nxt_srch ; If not a value of primary slot

ext_slt: ld c,apush bcpush hlcall enaslt ; Select Slot to scrutinizepop hlpop bc

di ; Start of test

ld a,080hout (03Ch),a ; Enables access to registers by addressing

ld a,(hl) ; The value read in address 080FFh (or 040FFh)and %00011111 ;inc a ; must be

;out (0FFh),a ; equal to the value

or %11000000 ;cp (hl) ; written to the port 0FFh

ld a,0out (03Ch),a ; Disables access to the registers by addressingout (0FFh),a ; Restore the page of system working area

ei

ld a,c ; Slot Number in the form F000SSPPjr z,mmm_found

nxt_srch: djnz mmm_srch_loop ; Continues the search

or 0FFh ; MMM not found -> A = 0FFh R = bit Z à 0ret

mmm_found:dec b ; MMM foundcp a ; Bit Z to 1ret

Example of calling the routine mmm_srch:

org 0100h ; Routine for MSX-DOS

ramad1: equ 0F342h ; Main-RAM Slot (04000h~07FFFh)ramad2: equ 0F343h ; Main-RAM Slot (08000h~0BFFFh)ramad3: equ 0F344h ; Main-RAM Slot (0C000h~0FFFFh)

mnrom: equ 0FCC1h ; Main-ROM Slotslttbl: equ 0FCC5h

example:ld h,080h ; 80h to search the bank 08000h~0BFFFhpush hlld b,16call mmm_srch

ld (mmm_slt),a ; Saving the number of slot found

pop hl ; H=80h (or 40h)ld a,(ramad2)call enaslt ; Restore the page of bank 08000h~0BFFFhret

mmm_slt: db 0ffh

Note : In this example the ramad2 system variable is used. The variables ramad0 to ramad3 are available only when at least one disk is installed.In a diskless environment, it is necessary to fnd the Main-RAM with his own routine. For this, it is good to know that some MSX have not all their RAM in the same slot. This is the case of the Sony MSX2 HB-500 for example. The following routine you will probably be useful if your program runs in a diskless environment.

Get the current status of a Slot

This routine in assembler is used to obtain the number of the selected slot of the corresponding memory bank.

; Name: mmm_gsln (get_slot_number);; Input: H = 0h, 040h, 080h ou 0C0h (Significant byte of the memory bank);; Output: A = Slot Number in the form F000SSPP;; Modify: All registers;; Size: 61 bytes;; Detail: Returns the slot address number of the memory bank to H;; note: Also works in MSX-DOS;

mmm_gsln:push hl ; Address of the bank of memory.xor ald iy,(mnrom)ld ix,rslregcall calslt ; A = status of current primary slotspop hlpush afld a,hand %11000000rlcarlcarlcald b,a ; Number of shift to be performed to

; retrieve the primary slot numberpop afinc b ; B should not be 0rlcald c,b

gsln_0: rrcadjnz gsln_0

ld b,cand %00000011 ; Current primary slot number of

; the memory bank given by H registerld hl,exptblld d,0ld e,aadd hl,debit 7,(hl)ret z ; Back if the slot is not extended in

; secondary slot (A = 000000PP).ld d,0ld e,4add hl,deld c,ald a,(hl) ; Secondary slots status in the form

; SS3SS2SS1SS0.rlca

gsln_1: rrcadjnz gsln_1 ; Number of rotations...

and %00000011 ; Secondary slot Numberrlcarlcaor %10000000or c ; A = Slot Number in the form F000SSPPret

Additional Information

Connected directly the PCB to an expansion BUS

Musical Memory Mapper can connect directly to an MSX extension Bus with a ribbon cable by soldering a connector with the place as you can see in the following image.

Use a narrow SCSI connector for ribbon cable. It will be necessary to cut the pins 1 and 5 because of the hole that keeps the PCB in the cartridge case.

The ribbon cable must not exceed twenty centimeters.

Notes:

- It is also possible to order a ready made version in suitable case but be careful because some expansion Bus have the sound input pin unconnected. In this case, only the Memory Mapper will work. You will have no alternative but to order a cartridge without sound chip unless you are able to add this pin.

- Some MSX has two polarizer on the Bus extension plug instead of one.

The ribbon cables with two polarizer bars are hard to fnd. The easiest solution would probably be to fle down the bar on the cable connector.

Compatibility list

Musical Memory Mapper cartridge was tested with the following MSX.

• MSX1 Canon V-20• MSX1 Philips NMS-8020• MSX1 National CF-2700• MSX1 Sony HB-20P• MSX1 Toshiba HX-10DP• MSX1 Yashica YC-64• MSX2 Mitsubishi ML-G1 (We must press the "DEL" key at startup when a memory

expansion is inserted in this MSX.)• MSX2 Philips NMS-8220• MSX2 Philips NMS-8235• MSX2 Philips NMS-8245• MSX2 Philips MNS-8250/8255• MSX2 Philips NMS-8280• MSX2 Sony HB-F700P• MSX2 Sony HB-G900• MSX2 Yamaha YIS-503 III КУВТ-2• MSX2+ Panasonic A1-WX• MSX Turbo R FS-A1ST (modes Z80 et R800)• MSX Turbo R FS-A1GT (modes Z80 et R800)

List of tested disk interfaces.

• CF/IDE Interface Sunrise• CF/IDE Interface by MM (cartridge derived from Sunrise)• MegaFlashRom SCC+ SD• MMC/SD Drive v.4.01 by Yeongman Seo (The MSX-DOS2 does not start for an

unknown reason)

The incompatible hardware is listed in red.